1. Field of the Invention
This invention relates to a laser coagulation system, and more particularly to a laser coagulation system adapted for use in an ophthalmological treatment in which a laser beam from a laser source is radiated into a patient's eye to develop great heat causing thermal coagulation at a predetermined portion of the biological organism in the eyeball of a patient.
2. Description of the Prior Art
There have long been known laser coagulation systems in which during an ophthalmic operation against diseases such as retina detachment, glaucoma, etc., a patient's eye is irradiated with laser energy, which is absorbed in a biological organism such as retina to develop thermal coagulation thereon for ophthalmological treatment. For this purpose, the laser coagulation system includes a laser beam projector for producing a laser beam from an argon or krypton laser, which is condensed to a laser beam of a predetermined diameter, directed toward a predetermined portion of the eyeball to be coagulated, and then focussed thereon as a laser spot for thermal coagulation.
The laser coagulation system further comprises a slit image projector for forming a slit image on the eyeball to illuminate the background and determine the portion of eyeball to be coagulated, and an observation equipment for observing the slit image and laser spot in the eyeball.
With such arrangement, the slit image projector is rotatably mounted on an instrument base about the vertical axis and includes two mirrors for directing slit light toward the patient's eye to form the slit image on the extension of the vertical axis. The laser beam projector is, on the other hand, arranged above the slit image projector and includes a mirror arranged adjacent to the two mirrors to project the laser spot in the vicinity of the slit image. The observation equipment is arranged outside of the slit image projector and mounted turnably about the vertical axis.
The mirror of the laser beam projector arranged adjacent to the mirrors of the slit image projector is displaceable or turnable vertically or horizontally by using an operating lever mechanically linked to or wire-connected to the mirror to displace or scan the laser spot in the vicinity of the slit image. This operating lever extrudes rearwardly from the observation equipment for easy access. The operating mechanism for the mirror is called a manipulator.
Such coagulation systems in the prior art have the drawbacks that the operating lever of the manipulator is mechanically dependent on the driving link or wire mechanism and disturbs the turning operation of the slit image projector or observation equipment. The manipulator is additionally provided with a spring for preventing the operating lever from falling down by gravity and returning it to a reference position. This disadvantageously makes it impossible to hold the operating lever to a position different from the reference position for a long time and to accurately displace the laser spot position in the eyeball. The operating lever is further arranged away from a control panel for controlling the instrument as a whole, thus requiring sophisticated operations.